1. Field of the Invention
The present invention relates to an electronic toll collection system and more particularly to an on-board electronic device which makes wireless communication with a stationary device installed at a toll gate for electronically collecting a toll.
2. Description of Related Art
Various systems for electronically collecting a toll at a toll gate have been proposed hitherto. An on-board electronic device for this purpose includes functions such as wireless communication with a stationary device installed at a toll gate, data processing, data memory and an information display for a passenger. Also, the on-board device must to include a security system for protecting monetary data stored therein and ensuring legitimate communication with the stationary device. The security system has to include a countermeasure function against any improper or illegitimate handling of the on-board device. Such improper handling must be discovered to quickly, and operation of the system has to be stopped temporarily. Moreover, the system or the on-board device which is temporarily inoperative must to be recovered after a certain measure has been taken against such improper handling. However, no system which satisfactorily performs the desired functions mentioned above has been proposed.